Possible to display better message for ScienceBase "404 Not Found" error?

[zdefne-usgs]

Is it possible to handle the "404 not found" errors in a more meaningful way? For example the Sciencebase page is down for maintenance at the moment and it returns "Site is down for required system maintenance." message as response for the following dataset:
http://cmgdata.usgsportals.net/#module-metadata/942d7a82-8992-4972-868e-5538a1c86cb5/bc1474bf-a6a8-4b92-a2c1-9ca130b9e644

Is it possible to reflect this with something like a pop up message instead of just the empty tiles?

if header.status_code== '404 Not Found':
   pop_up_message = response.message?
   pop_up_message.show()